1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2012 ARM Limited
12 */
13
14 #include <linux/clkdev.h>
15 #include <linux/clk-provider.h>
16 #include <linux/err.h>
17 #include <linux/of.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/vexpress.h>
21
22 struct vexpress_osc {
23 struct regmap *reg;
24 struct clk_hw hw;
25 unsigned long rate_min;
26 unsigned long rate_max;
27 };
28
29 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
30
vexpress_osc_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)31 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
32 unsigned long parent_rate)
33 {
34 struct vexpress_osc *osc = to_vexpress_osc(hw);
35 u32 rate;
36
37 regmap_read(osc->reg, 0, &rate);
38
39 return rate;
40 }
41
vexpress_osc_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)42 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
43 unsigned long *parent_rate)
44 {
45 struct vexpress_osc *osc = to_vexpress_osc(hw);
46
47 if (osc->rate_min && rate < osc->rate_min)
48 rate = osc->rate_min;
49
50 if (osc->rate_max && rate > osc->rate_max)
51 rate = osc->rate_max;
52
53 return rate;
54 }
55
vexpress_osc_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)56 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
57 unsigned long parent_rate)
58 {
59 struct vexpress_osc *osc = to_vexpress_osc(hw);
60
61 return regmap_write(osc->reg, 0, rate);
62 }
63
64 static const struct clk_ops vexpress_osc_ops = {
65 .recalc_rate = vexpress_osc_recalc_rate,
66 .round_rate = vexpress_osc_round_rate,
67 .set_rate = vexpress_osc_set_rate,
68 };
69
70
vexpress_osc_probe(struct platform_device * pdev)71 static int vexpress_osc_probe(struct platform_device *pdev)
72 {
73 struct clk_init_data init;
74 struct vexpress_osc *osc;
75 struct clk *clk;
76 u32 range[2];
77
78 osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
79 if (!osc)
80 return -ENOMEM;
81
82 osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
83 if (IS_ERR(osc->reg))
84 return PTR_ERR(osc->reg);
85
86 if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
87 ARRAY_SIZE(range)) == 0) {
88 osc->rate_min = range[0];
89 osc->rate_max = range[1];
90 }
91
92 if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
93 &init.name) != 0)
94 init.name = dev_name(&pdev->dev);
95
96 init.ops = &vexpress_osc_ops;
97 init.flags = 0;
98 init.num_parents = 0;
99
100 osc->hw.init = &init;
101
102 clk = clk_register(NULL, &osc->hw);
103 if (IS_ERR(clk))
104 return PTR_ERR(clk);
105
106 of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
107 clk_hw_set_rate_range(&osc->hw, osc->rate_min, osc->rate_max);
108
109 dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
110
111 return 0;
112 }
113
114 static const struct of_device_id vexpress_osc_of_match[] = {
115 { .compatible = "arm,vexpress-osc", },
116 {}
117 };
118
119 static struct platform_driver vexpress_osc_driver = {
120 .driver = {
121 .name = "vexpress-osc",
122 .of_match_table = vexpress_osc_of_match,
123 },
124 .probe = vexpress_osc_probe,
125 };
126
vexpress_osc_init(void)127 static int __init vexpress_osc_init(void)
128 {
129 return platform_driver_register(&vexpress_osc_driver);
130 }
131 core_initcall(vexpress_osc_init);
132
